System of motor control.



W. NAUMANN. SYSTEM OF MOTOR CONTROL.

APPLICATION FILED was 10, 1008.

1,071,778. Patented Sept. 2, 1913.

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WITNESSE'S'. [NS/ENTER UNITE STATES rnfrssir OFFICE.

WILHELM NAUMANN, or BERLIN, GERMANY, ASSIGNOR. 'ro GENERAL ELECTRIC comrnntn conrom'rlonor NEW YORK.

SYSTEM OF MOTOR CONTROL.

To allwkom it may concern:

. Be it. known that I, lVIL-HELALNAUMANN, a subject of the King of,PrusSia,resicli11g at Berlin, Germany, have invented certain new and useful Improvem nts i Sy t ms of Motor Control, of which t e iollo ing is a specification.

My. invention relates to the control of electric motors for driv'ing'hoists and similar apparatus. For this kind of work, three sets of connections are frequently .desirablc,-first for opcrat-ion'as a motor for hoisting;-second for operation as a motor in lowering a light load; and third, for operation as a braking generator for lowering heavy loads. For hoisting, a series characteristic is desirable, so that it is customary to employ a series-wound 1 or compoundwound motor. If the-conncctious-for lowcr ing a light load are made in the usual Way, by reversing the armature and connectingit'in-scries with the field winding, th re is dangerof too great a specd, since the field is" weakened more and lIlOIfl-RS the armature speed increases.

The objects of my invention'are, to pro- 'duce a novel controlsystem in which-power may be applied to the motor for lowering the load without operating the motor at too great a. speed, to connect the armature and field winding of the motor in a closed circuit during lowering so that in case the power fails a dynamic brake will-be applied to the motor, and to connect the motor in a local or dynamic braking circuit when the controller is in the off-position. To this end, my invention consists in certain novel features whereby these objects may be attained.

My invention will best be understood by reference to the accompanying drawings, in which- Figure 1 shows diagrammatically anelcc trio motor with its control system arranged in accordance with my invention; and Figs. 2, 3 and 4 are diagrams of connections established by the control system of F ig. 1.

In Fig. 1. A represents the armature of a, motor which I have shown diagrammatically, geared to a hoisting drum B. sents the main field of the motor, which, for hoisting, is connected in series with the motor-armature. The motor may also be provided with a shunt field D, thereby Specification of Letters Patent.

making the motor compound-Wound. "This Patented Sept. 2, 1913 Application an June 10, 1908. Seria1No.437 ,$38,

shunt-field is not, however, essential. E represents a reversing switch for connecting the motor to the line F, for either direction of rotation, and also serving in its off position to disconnect the motor from the line and connect it in short-circuit for braking. G represents a resistance for controlling the current in the motor-circuit. The switch E is shown diagrammatically with its-contacts developed in a plane surface. \Vhcn -the switch is moved so as to bring the left-handmovable contacts into engagement, a circuit is closed from the upper line-wire F through resistance G, field winding C armature A, to the lower line wire F, which connections are shown in Fig.2. The shunt winding D,

it employed, is connecteddirectly across the line. The motor thus starts as acompound or series wound motor, according, as thle field-winding D is or is not-employed. A further movement of switch E in the same direction cuts resistanceG out ofcircuit stcpby-st-ep. These hoisting connections are those ordinarily employed. When the switch E is returned to off-position, as shown, the motor-armature is disconnected from the line and is connected in a local or dynamic bra-king circuit with the main field winding 0. The auxiliary shunt winding D may or may not be left connected to the line.

This connection is shown in Fig.3, and is that frequently employed for braking an electric hoist.

When the switch E is moved to bring the right hand movable contacts into engagement with the contact fingers, connections are established for motor-operation for lowering a light load. In this position of 'the switch E, the lower line-wirc F is connected to the junction of armature winding and field winding C, while the armatureterminal that in hoisting was connected to.

this line-wire is now connected to an intermediate point on resistance G as is shown in Fig. 4.. This places the armature winding and field winding C in parallel relation, and with the direction of current in the armature reversed. The motor consequently operates to lower the (load, but an increase in armatur speed-an voltage reduces the voltage, drop in the resistaiice and so strengthens themotor field, thereby limiting the speed of moton. Continuing the movement of switch E in the same direction, the point nfconncotion of the armature to resistance G isgradually right end; of said dynamic braking circuit:

the voltage impressed on ',t he armati consequently 1ts speed," o-wlthcu' right, as viewed 1n=,E1 g. 4,

changingthecurrent'in the'field winding With the joint of connection of the armature-with the resistance Gr; at the extreme '-resi stance,' the motor operates as ar puresh'unt motor.

fljIt willfbe noted that the control above described requires only'a small number of leads." The armature- A, fieldnwindin'g C andresistance G may be permanentlyconneeted in series. For hoisting, the three are connected in'series relation tothe source, while for lowering, asshown in Fig. 4, the field winding" C and resistance Gare-connected in series withthe 'source, while the free terminal of armature-A is connectedto a' pointon' the resistance, or,'-iin othe g o s', the armature is cOnnectedQin-a circuit-which? field winding- C1 and a tesi'stanodfiylf, aftel," starting the load'ofthe hoistdownward the; controller 'isreturned to the off paralleh'circuits are "thcff supply mains F, whereby the windingar'o'f'. the motor are Leftooi1nected in' lean-as;

What I claim asnew, and, to by Letters Patent ofytheUniM 1. In combination, an electric-motor, are;

"sistance and means the ar ria-- ture an fieldi of motorfandsaid-resistl ance inser-ies to the'source for operationrin one direction and for connecting" the field winding and said resistance in series to the 1 souroe an'dthe armature in shunt to-said field and'more or less ofsaid resisb,

ance foroperationin the other direction.' 2 In combination,- an electric moton, a resistance, thewarmature and field windm'g'of' the motor an'd resistancebeing permanently 'connectedin series, a source of current, and

means-for connecting the armature, field winding and resistanoein series to' saidsource for operation in one direction and for connecting the field winding and. said resistance in series to the source and connecti theE-free terminal of the armature to di event: ijnts on-said' resistance for operationiin t lig'opposite direction.

3;lncombination, anfelectric motor, a re'-' sistance,--a .sourceof current, and means for connecting itheifieldwinding of said motorandsaidfresistance'in series to the source and the armature inshunt to said field Wlilding and more or less of "said resistance.

"-4.111 combination, a r-[electric motor, a res1'stance,,the armature and field winding of-the'motor and the said resistance being 'perinanentlyponnected in; series, a source-of current, and means for connecting the field .winding-and saidfresis'ta'ncein series to-tiie source and connecting the free'terminalof lin combination with an electric motor, means "for connecting a field winding of the .motor series with the armature for opera-- tion in one direction, for connecting the field winding of the motor in series with a resistance and inparallel with the armature for operation in the opposite direction, and for connecting, said field winding and armature inja local or dynamic braking circuit.

6., In combination with an electric motor, a'sdurce of current, means for connecting said motor to the source for operation in one direction with afield winding in series with the armature, for connecting the field winding of the-"motor in series with a resistance and in'parallel with the armature across said source for operation in the opposite-direction, and for disconnecting the motor from-t-he source andwonnecting the armais in'- parallel with ai'circuit containmg the {are and said field windi .i 1 1 or d 'namic braking circuit.

5 7. In combination with an electric motor,

a-source of current, a reversing switch arranged in one position 'to'connect the motor Ito' thes'ource with the armature in series fieldwinding, and in another position-to connect the motor to the source with the-field winding in series with a resistance acros the-source and in parallel with the ar- 'm'ature,"and in a third position to disconnect "the motor from the'source and to connect the armature and said field winding in a local or dynamic braking circuit.

-' 8. In combination, an electric motor having its armature winding and a field windpermanen'tly connected -:in series, a sourceoftcurre'nt, a resistance, and means for connecting said, windings in series with said;resi st ance to the source for operation in one direction, and for connecting said field and said resistance in series to the source andconnecting the free terminal of the armature to a point on'said resistance for operation in the opposite direction.

- 9. In combination, an electric motor having its armature winding and afield winding permanently connected in series, a source of current, a resistance, means for connecting said windings in series with said resist ance to the source for operation in one direction, and for connecting said field winding and said resistance in series to the source and connecting the free terminal of the armature to a-point on said resistance for operation in the opposite direction, and means circuit.

10. In combination an electric Ino- -tor,-a,; reversing switch therefor arranged to winding .in series witha resistance and in ba'rallel with the armature, and to connect 3 .for varying the amount'of said resistance in the armature to said field winding in a local or dynamic braking circuit.

11. In a control system for electric hoists, an electric motor, a controller so arranged that in lowering the load the field winding of the motor will be connected in a circuit containing a resistance and the armature of the motor will be connected in a parallel circuit with said field winding and resistance, thereby starting the load downward, and means for disconnecting the parallel circuits from a supply main, thereby leaving the windings of the motor connected in a local or dynamic braking circuit.

. 12. In combination, an electric motor. the armature and field winding of said motor being permanently connected in series, a source of current, and means for connecting the armature, field winding and a resistance in series to said source for operation in one directio-nand for connecting the field winding and a resistance in series to the source and the armature in a parallel circuit for operation in the opposite direction.

13. In combination, an electric motor, the armature and field winding of said motor being permanently connected in series, a source of current, and means forconnecting the armature, field winding and aresistance in series to said source for operation in one direction and for connecting the field winding and a resistance in series to the source and the armature in a parallelcircuit for operation in the opposite direction, and for disconnecting said source, thereby leaving the windings of the motor connected in a local or dynamic braking circuit.

14. In combination, an electric motor, a resistance, the armature and field winding of the motor being permanently connected in series, a source of current, and means for connecting the armature, field winding and resistance in series to said source for operation in one direction and for connecting the field winding and said resistance to the source and connecting the free terminal of the armature to difl'erent points on said resistance for operation in the opposite direction.

15. In combinatioman electric motor, a resistance, the armature and field winding of the motor being permanently connected in series, and means for connecting the armature and field of said motor and said resistance in series to the sourte or operation in one direction and for connecting the field winding and said resistance in series to the source and the armature in shunt to said field'winding and more or less of said resistance'for o )eration in-the other direction.

16.-In com ination, an electric motor, a resistance, the armature and field winding of the motor being permanently connected in series, a source of current, and means for connecting the field winding and said resistance in series to the source and connecting the free terminal of the armature to different points on said resistance.

17. In a control system for electric mo tors, an electric motor having a series field winding, and a controller, which, when operated to cause the load to be lowered, first connects the armature and the field winding of the motor in parallel paths, the arallel path containing the field winding a so containing a resistance, and connects said parallel paths across the supply mains, and sub sequently disconnects said parallel paths .from the supply mains, leaving the armature and field windings of the motor connected in a local or dynamic braking circuit. 18. In a control system for electric hoists,

an electric motor having a series field windmg, a resistance for said motor, and a controller having means which, when operated to cause the load to be lowered, first 'connects the armature and field windings of the motor in parallel paths and connects saidparallel paths across the supply mains with the resistance in series therewith and leaves the armature and field windingsof the motor in a local or dynamic brakingpircuit.

19. In a control system for electric hoists, an electric motor having a series field winding, a oontroller'having stationary contacts and a movable member having contacts cooperating therewith, and resistance sections connected to certain of said stationary contacts, the arrangement being such that when the movable member of the controller is moved in one direction from the off-position,

the motor and series field windin are connected in series across the supply mains and in series with a resistance in such a manner as to cause the motor to hoist the load, further motion (if said movable member of the controller reducing lsaid resistance and,

ance section, the connection being such as to cause the motor to drive the load downward, the motion of the movable member of the controller toward the oil-position then disconnecting said parallel circuits from the supply mains and leaving the windings of the motor connected in a local or dynamic bl'akin circuit.

20. lit a control system for electric motors, a closed circuit containing the arma' ture, a field winding and a resistance, and means for connecting said closed circuit to the line so as to form two parallel circuits, one containing the armature and the other the field winding in series with a resistance.

21. In a control system for electric motors, a closed circuit containing the arma ture, a field windin and a resistance, a connection to one sife of the line between the armature and the field winding, and a connection from the resistance to the other side of the line.

In acontrol system, a source of current, an electric motor having a series field winding, and means for connecting the armature and field Winding of said motor and a resistance in series to said source for op eration in one direction, and for connecting the field winding and a resistance in series to said source and the armature in shunt to said field windin and resistance for operation in the other direction.

23. In a control system, a source of current, an electric motor having a series field winding, and means for connecting the armature and field winding of said motor and a resistance in series to said source for operation in one direction, for connecting the field winding and a resistance in series to said source and the armature in shunt to said field winding and resistance for operation in the other direction, and for disconnecting said source thereby leaving the windings of the motor connected in a local or dynamic braking circuit.

24. In a control system for electric hoists, supply mains, an electric motor having a series field winding, and a controller, which, when operated to cause the load to be hoisted, connects the armature and field winding of said motor in series with a resistance across said supply mains, and, which, when operated to cause the load to be lowered, connects the armature and the field Winding of the motor in parallel paths, the parallel path containing the field Winding also containing a resistance, and connects said parallel paths across said supply mains, and subsequently disconnects said parallel paths froma supply main, leaving the, windings of the motor connected in a local or dynamic braking circuit.

In Witness whereof I have hereunto set my hand this 18th day of May, 1908.

VVILHELM NAUMANN, \Vitnesses JULIUs RUMLAND, OSKAR SINGER.

Copies of this patent maybe obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

